Crystalline polyamides from mixtures of TA and IA and mixtures of TMHMDA and HMDA wherein the TA content is at least 80 percent of the total acid moieties have not been obtained by the prior art. In fact, U.S. Pat. No. 3,382,216 (1968) teaches that the preparation of polyhexamethylene terephthalamide cannot be effected through melt condensation processes.
U.S. Pat. No. 3,150,117 (1964) discloses that linear amorphous film forming polyamides can be prepared from dicarboxylic acids and alkyl-substituted saturated hydrocarbons; however, the mixture of trimethylhexamethylene diamine and hexamethylene diamine is not disclosed in this reference.
U.S. Pat. No. 3,294,758 (1966) discloses a polyamide which is prepared from terephthalic and isophthalic acid and a mixture of diamines consisting of 5-30 weight percent hexamethylene diamine and 95-70 weight percent trimethylhexamethylene diamines. This patent teaches that compositions having more than 30 weight percent hexamethylene diamine are brittle.
U.S. Pat. No. 4,410,661 (1983) discloses a polyamide obtained from (i) a mixture of 70-100 weight percent trimethylhexamethylene diamines and 30-0 weight percent hexamethylene diamine and (ii) 0-100 weight percent terephthalic acid and 100-0 weight percent isophthalic acid.
Crystalline polyphthalamides obtained from terephthalic acid mixtures of hexamethylene diamine and trimethylhexamethylene diamine have been disclosed in commonly owned U.S. Pat. No. 4,495,328, which issued from application Ser. No. 601,909, which was a continuation-in-part of application Ser. No. 466,903 filed Feb. 16, 1983 concurrently with application Ser. No. 466,901. This patent is incorporated herein by reference.
Other U.S. patents of interest include: U.S. Pat. Nos. 3,825,516 (1974); 3,962,400 (1976); 3,941,755 (1976); 3,627,736 (1971); and 3,692,749 (1972). All of these patents disclose amorphous polyamides.
In reviewing all these references, it is clear that the crystalline polyphthalamides manufactured from mixtures of TA and IA and mixtures of HMDA and TMHMDA wherein the TA content is at least 80 percent of the acid moieties, which polymers have improved tensile strength, are unknown to the prior art. Additionally, such polyamides which, when filled, have heat deflection temperatures of about 240.degree. C. to about 305.degree. C. are unknown in the prior art.